Container, or pipeline, wall mountable measuring devices utilize, in general, a process connection, which is connected, on the one hand, with a sensor element and, on the other hand, with a housing. The sensor element is mountable via the process connection in such a manner to the container or pipeline that it protrudes inwardly into the interior of the container or pipeline or at least faces the interior. The housing remains outside of the container or pipeline and accommodates, as a rule, electronic components of the measuring device. In order to prevent damage to these electronic components, a fixed and sealed connection of housing and process connection is required.
The process connection is, as a rule, made of metal. A housing, likewise of metal, is, for example, weldable with the process connection. When a housing is made of synthetic material, e.g. plastic, this kind of joining technology is not feasible. A first option is to provide a screw thread on each of two parts to be connected together and then screw them together. Known from Offenlegungsschrift (German Laid Open Application) EP 0660482 A1, for example, is a pressure sensor having a cylindrical housing, into which a housing lid is screwed. Providing process connection and housing each with a screw thread is, however, relatively complicated, the more so, since, for twist resistance, an adhesive is supplementally required.
Another connection option involves introducing a neck shaped section of one of the parts into the other part and to secure the assembly by means of a snap ring. This connection is, however, not shape-interlocked and additionally not secured against twisting of one part relative to the other part.